Device controller with intracontroller communication capability, conveying system using such controllers for controlling conveying sections and methods related thereto

ABSTRACT

Featured is a device controller in a system having a multiplicity of such controllers and a conveying system and method for controlling a multiplicity of devices using such controllers. Each controller includes a plurality of bi-directional communications ports, a processor that processes information and provides outputs, where at least one output controls the device, and an applications program for execution within the processor that includes instructions and criteria for processing the information and providing the processor outputs. Specifically, the applications program includes instructions and criteria for communicating information between and among controllers; instructions and criteria for processing information received by a controller; and instructions and criteria for modifying the operation of a device responsive to the communicated information. For a conveying system having a multiplicity of conveying sections, a controller is provided for each section. Preferably, the applications program for a conveying system controller also includes the instructions and criteria needed to operate any one of a number of different conveying section types. Further, the conveying system controller includes a memory for storing parameters that are used so the corresponding conveying system section operates in the desired fashion.

FIELD OF INVENTION

The present invention relates to device controllers and operatingmethods therefor and more particularly conveying systems employing suchcontrollers locally.

BACKGROUND OF THE INVENTION

Existing control systems and control methodologies, particularly thosefor conveying systems, employ some form of centralized control overmultiple device controllers. For example, two device controllers arehard wired interconnected to a programmable logic controller (PLC) or aplurality of PLCs, each being hardwired to device controllers, are hardwired connected to another central PLC. To effect a change in theoperation of one device in response to changing conditions for anotherdevice, the PLC identifies the changing conditions and sends a signal tothe other controller.

Such systems are difficult to modify in the field by the user (i.e, notuser friendly). System modifications typically involves re-configuringor replacing each control component (i..e, controller and PLC) in thesystem. As such, these types of systems are expensive and time consumingand have little flexibility for field modification.

Conveying systems traditionally have been custom designed withcentralized controls and complex customized software for trackingarticles or goods in movement in the system. Modifications to suchsystems entail adjustments to the centralized controls, revision to thecustomized software and the de-bugging required following such changesto assure proper system operation. Further, because the software andcontrols for each system is customized for each system, it is difficultto combine the control logic with the mechanicals of the conveyingsystem.

There is, therefore, a need for controllers that communicate with eachother on a local area basis to control the operation of systems ordevices connected to the controllers and need for controllers thatde-centralize these control function. Additionally, there is a need fora controllers which do not require hard wired interconnections but usecommunication protocols and equipment as a means for communicatingbetween controllers. There also is a need for a conveying system thathas increased flexibility and controls the flow of goods or articlesthrough the system without centralized control and customized software.Moreover, there is a need for a conveying system that is modularized indesign and operation so customized engineering is not required.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide acontroller that, through communication with other controllers, controlsthe system or devices using the controllers.

It is another object of the present invention to provide a controllerthat de-centralizes the control process.

It is a further object of the present invention to provide a conveyingsystem using such a controller that controls individual sections of theconveying system.

It is yet a another object of the present invention to provide aconveying system controller that adjusts the operation of one conveyingsection in response to communications from other controllersrepresentative of local system performance or problems.

It is yet a further object of the present invention to provide aconveying system controller, a universal controller, that isre-configurable by the user to drive any of the conveying sectionsmaking up the conveying system.

It is still yet another object of the present invention for thecontroller to be re-programmed by the user locally or from a centrallocation using the controller communications network.

The instant invention features a device controller that is used in asystem of such controllers as well as a method for controlling theoperation of a device using such a device controller. The devicecontroller includes at least one, preferably at least two,bi-directional inflow and outflow communications ports, a processor andan applications program for execution with the processor. The processorprocesses information and provides outputs, where at least one outputcontrols the device. The applications program includes instructions andcriteria for processing the information and providing the processoroutputs. Specifically, the applications program includes instructionsand criteria for communicating information between and amongcontrollers; instructions and criteria for processing informationreceived by a controller; and instructions and criteria for modifyingthe operation of a device responsive to the communicated information.

The device controller further includes a read/write memory for storingdata and parameters that control the operation of the applicationsprogram. The applications program also further includes instructions andcriteria for controlling data storage in the read/write memory as wellas instructions and criteria for real time tracking of data related tosystem performance.

To communicate information between and among the controllers of thesystem, a communications link is established between each pair ofcontrollers. This link is established by electrically interconnectingone bi-directional outflow port of one controller to one bi-directionalinflow port of another controller.

The controller of the instant invention may be programmed orre-programmed by means of the RS232 I/O port or by means of thecommunications network established by the electrically interconnectedcontrollers. To effect programming/re-programming of a controller viathe communications links, the applications program further includesinstructions and criteria for reprogramming the processor/controllerresponsive to instructions and information communicated through abi-directional inflow port.

Also featured is a conveying system having a multiplicity of conveyingsections, where each section is provided with a local controller. Thelocal controller for each conveying section, the corresponding conveyingsection includes at least one, preferably at least two, bi-directionalinflow and outflow communications ports, a processor and an applicationsprogram for execution with the processor.

The processor processes information and provides outputs, where at leastone output controls the corresponding conveying section. Theapplications program includes instructions and criteria for processingthe information and providing the processor outputs. Specifically, theapplications program includes: instructions and criteria forcommunicating information among and between each controllers of themultiplicity of conveying sections; instructions and criteria forprocessing information received by the controller for the correspondingconveying section; instructions and criteria to control the normaloperation of the corresponding conveying section, and instructions andcriteria for modifying the operation of the corresponding conveyingsection responsive to information communicated from the controller ofanother conveying section.

Each conveying section controller further includes a read/write memoryfor storing data and parameters that control the operation of theapplications program. The applications program also further includesinstructions and criteria for controlling data storage in the read/writememory.

A conveying system according to the instant invention utilizes amultiplicity of different section types to transport articles in acontrolled manner. For example, the conveying system of the instantinvention may include straight sections, accumulation sections, spacersections, index sections, diverter sections and merge sections. As such,the applications program in each conveying section controller,preferably includes the instruction and criteria to control theoperation of any of these different section types.

The applications program accesses the control routines of the specificto the operation of a given type of conveying section (e.g., an indexsection) by evaluating the data and configuration parameters stored inthe read/write memory. For example, the section type is a parameter thatis stored in a data table set up in the read/write memory.

In operation, data relating to the articles on the correspondingconveying section is stored in the read/write memory. The applicationsprogram also further includes instructions and criteria for real timetracking of articles on each conveying section. Thus, a remotely locatedhost computer, using the communications network established between andamong the controllers, can make an inquiry to any controller for suchreal time information. Further, when articles are transferred from anupstream conveying section to a downstream section, the data stored inthe read/write memory of the upstream controller is communicated to thedownstream controller.

In specific embodiments, the conveying system further includes amultiplicity of tracking devices to sense the presence of an article.These tracking devices are disposed at the end or beginning of a givensection and the section's controller is appropriately configured for theposition of its tracking device. The tracking devices are disposed atvarious locations through out the conveying system required for properoperation of a conveying section(s) and the system. For example, atracking device would be located between the end of a spacer section andthe next section in the conveying system.

For the first section of the conveying system, a mechanism or device isprovided at or proximate the beginning of the first section to provide apositive indication of each article entering into the conveying system.This mechanism or device may be a tracking device, a photo eye or otherdevice known to those in the art for use in detecting the presence of anarticle. The controller of the first section in response to signals fromthe mechanism/device assigns a identifier to the article and causes theidentifier to be stored in the read/write memory.

A tracking device also is located between the first and second sections,and it is used to determine the length of the articles passing throughthe first section as well as the presence of the article at the end ofthe first section. The first and second sections controller operates inconjunction with their tracking device, so the determined length foreach article is stored, along with the associated identifier in theread/write memory. Alternatively, the length is determined by thetracking device disposed at the beginning of the first section and thefirst section controller causes both the identifier and determinedlength to be stored in the read/write memory.

Similar to the above described device controller, a communications linkis established between each pair of controllers of the conveying systemby electrically interconnecting one bi-directional outflow port of oneconveying section controller to one bi-directional inflow port ofanother conveying section controller. Further, the conveying systemcontrollers may be programmed or re-programmed by means of the RS232 I/Oport or by means of the communications network established by theelectrically interconnected controllers and the instructions andcriteria included in the applications program.

BRIEF DESCRIPTION OF THE DRAWING

For a fuller understanding of the nature and desired objects of thepresent invention, reference should be made to the following detaileddescription taken in conjunction with the accompanying drawing figureswherein like reference character denote corresponding parts throughoutthe several views and wherein:

FIG. 1 is a schematic block diagram of a controller according to theinstant invention;

FIG. 2 is a block diagram of an exemplary communications network forcontrollers of the instant invention;

FIG. 3 is a plan view of an exemplary conveying system using thecontroller of the instant invention;

FIG. 4 is an exemplary data table of the information concerning thearticles in transit that is stored in each conveying system controller;and

FIGS. 5A-I is a flow diagram of the control logic for a universalcontroller of a conveying section.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the various figures of the drawing wherein likereference characters refer to like parts, there is shown in FIG. 1 aschematic block diagram of a controller 10 of the instant invention thatcontrols an external device 2 and which can receive input from anexternal device 4, such as the tracking signal generating device 122(FIG. 3) described hereinafter.

The controller 10 of the instant invention, as described hereinafter, isuser friendly and easily modified by factory personnel or the users inthe field. Instead of one central processor following highly complicatedinstructions, as is done in prior art systems, each controller 10provides for local area control over the devices and system.

Preferably, each controller 10 of a conveying system is preprogrammedwith the control routines for all the individual conveying systemmodules or sections so the controller 10 is a universal controller. Inoperation, configuration parameters are programmed and stored in theprocessor 12 so as to enable the specific control routines required tooperate a conveying section as a particular section type (e.g., indexingsection). In addition, to controlling the operation of each section, thecontroller 10 tracks the position of the boxes, goods or articles oneach section of the conveying system and can direct the finaldestination of specific boxes. articles, etc. That is, at any time eachcontroller 10 in the conveying system is being operated so the identityof each box/article on each section is retrievable by the controller.

The controller 10 includes a processor 12, status lights 16, a battery18 and an RS232 I/O port 20. Also included is at least one andpreferably two inflow bi-directional communications ports 14a,b and atleast one and preferably two outflow bi-directional communications ports15a,b. The bi-directional communications ports 14a,b;15a,b arepreferably RS485 connectors with two RJ31X modular connections. Theindividual controllers 10 are interconnected to each other forbi-directional communications therebetween by means of a twisted eightwire telephone type cable 30 (FIG. 2).

The controller 10 is powered in any of a number of ways. In oneembodiment, electrical power is supplied to the controller via thetwisted cable 30 (FIG. 2) interconnecting the communications ports14a,b;15a,b of each controller. Thus, each of the controllers 10 ispowered from a central source. The central power supply provides powerin the range of from about 20 Vac to about 52 Vac and preferably isabout 24 Vac or about 48 Vac. Alternatively, each controller 10 or agroup of controllers are connected to a power supply in the abovevoltage ranges.

The battery 18 is a 3 V Lithium coin cell or any long-life type ofbattery known in the art. The battery 18 supplies back-up power to theread/write memory 22 comprising the controller 10 in the event of apower failure so data is retained until power is restored. For aconveying system application, the information retained includes thearticle tracking information and configuration parameters for eachsection. Also included is information concerning the articles or boxeson the section and any sorting or routing instructions for thesearticles/boxes. Alternatively, or in addition to the battery 18, thecontroller may use non-volatile memory types that retain informationwhen there is a power failure.

The status lights 16 are a plurality of LED indicators that are intendedto help a user troubleshoot the controller 10. The status lights alsoprovide a visual indication of the status of the controller's operationand outputs from the relays and TRIACS of the controller. The lights mayflash slowly, flash rapidly or may be lit steadily. For example, thestatus lights representative of a controller's operability may be litcontinuously when the controller 10 is locked up whereas they flash atsome rate during normal operation.

The RS232 I/O port 20 provides a bi-directional communications interfacebetween the processor 12, including the EEPROM 24 and NVRAM 22, and anexternal device such as programming terminal or a computer such as anpersonal computer. The I/O port 20 is one means for inputting theparameters required to configure or re-configure a given controller. Asdescribed below, the controller(s) also may be configured/re-configuredby a centrally located computer that communicates to each controllerusing the controller communications network 100 (FIG. 2).

The processor 12 preferably includes a non-volatile random access memory(NVRAM) 22, an EEPROM 24 and a central processing unit 26. Theapplications program or software routines, hereinafter described inconnection with FIGS. 5A-I, are preferably stored on the EEPROM 24 whichis easily removed in the field for replacement. The configurationparameters preferably are stored in the NVRAM 22 so they are easilychanged in the field, particularly by the user.

To update the applications program for any of the conveying sections ofa conveying system according to the instant application, an EEPROM isprogrammed in the factory and sent out to the field for installation.Because of the modularity of the conveying system sections and theinteractive communications between controllers during system operation,further debugging prior to full system operation is not required for theinstant invention. This saves time and money in comparison to knownsystems that are customized for a given application which limits theability to factory test or validate the applications program prior toinstallation.

The NVRAM 22 stores data and any parameters required for the operationand/or configuration of each controller 10. For example, in a conveyingsystem application, data regarding the boxes or articles on a sectionand any related tracking and routing data for each of these boxes orarticles is stored in the NVRAM. Further, the configuration parametersrequired to enable the control routines for a given section type of aconveying system are also stored therein.

The central processing unit 26 preferably is a PIC17C43 by MicroChipCorp., and alternatively it may be PIC17C44 by MicroChip Corp. Thesoftware routines stored in the EEPROM 24 are loaded into the centralprocessing unit 26 and specific routines are enabled by means of theconfiguration parameters retrieved from the NVRAM 22. The centralprocessing unit 26 executes the program and routines therein so as tocontrol the device 2. For example, in a conveying system the centralprocessing unit 26 outputs signals to control a given conveying systemsection and thereby control the flow of boxes or articles (i.e.,product) through the section and in the system. Also, the centralprocessing unit 26 would direct information to be retrievably stored inthe NVRAM 22 concerning an article or box on the section.

As noted above, the controllers 10 of the instant invention areinterconnected to each other for communications by appropriatelyinterconnecting the inflow and outflow bi-directional communicationsports 14a,b; 15a,b of at least two controllers. There is shown in FIG. 2a block diagram of an exemplary communications network 100 for aplurality of controllers 10a-g.

The controllers 10a-g preferably are connected to each other using a"daisy chain" topology. Starting from the upstream most point, the firstcontroller 10a, a connecting cable 30 is interconnected to an outflowbi-directional communications port 15a of the first controller 10a andinto an inflow bi-directional communications port 14a of the secondcontroller 10b. Thus, a bi-directional communications link isestablished between the first and second controllers 10a,b for thecommunication of data and information therebetween. In a similarfashion, there is established a communications link between the sixthand seventh controllers 10f,g.

In some situations, information and data flow is split between twodownstream paths such as that shown for the second, third and fourthcontrollers 10b-d. For example, when goods or boxes are diverted fromone line into one of two lines in a conveying system. Again startingwith the upstream controller, the second controller 10b, two connectingcables 30 are connected to the outflow bi-directional communicationsports 15a,b of the second controller 10b. The other end of oneconnecting cable 30 is connected to an inflow bi-directionalcommunications port 14a of the third second controller 10c and the otherconnecting cable is connected to an inflow bi-directional communicationsport 14a of the fourth controller 10d. Thus, a bi-directionalcommunications link is established between the second and thirdcontroller 10b,c and the second and fourth controllers 10b,d for thecommunication of data and information therebetween.

In some situations, information and data flow from two upstream paths iscombined into one downstream path such as that shown for the fourth,fifth and sixth controllers 10d-f. For example, when goods or boxes fromtwo lines of a conveying system are being merged into one line. Againstarting with the upstream side, a connecting cable 30 is connected toan outflow bi-directional communications port 15a of the fourthcontroller 10d and connected to one inflow bi-directional communicationsport 14a of the sixth controller 10f. Similarly, a connecting cable 30is connected to an outflow bi-directional communications port 15a of thefifth controller 10e and connected to the other inflow bi-directionalcommunications port 14b of the sixth controller 10f. Thus, abi-directional communications link is established respectively betweenthe fourth and sixth controllers 10d,f and the fifth and sixthcontrollers 10e,f for the communication of data and informationtherebetween.

In addition, to forward and backward communications between controllersthat are directly connected (e.g., the first and second controllers10a,b), the communications network 100 permits such communicationthroughout the entire network 100. For example, the seventh controller10f may communicate with the first controller 10a by means of thecommunications links established respectively between the first andsecond controllers 10a,b, the second and fourth controllers 10b,d, thefourth and sixth controllers 10d,f and the sixth and seventh controllers10f,g. Thus, the communications links not only establish a localcommunications links between individual controllers but allowsestablishes communications links between any controller in the network.

Also shown is one means for interconnecting an external device, such asscanner 6 and/or a host computer 8, to the controller communicationsnetwork 100. The host computer 8 is interconnected to a buffer device 9which in turn is interconnected to one of an inflow bi-directionalcommunications port 14a of the first controller 10a. Similarly, ascanner 6 may be connected to a communications port of the buffer device9. The use of a buffer device 9 in connection with the host computer 8enables forward and backward communication between the controllers 10a-gas well as forward and backwards communications between the hostcomputer and any one or all of the controllers 10a-g of thecommunications network 100. For example, the host computer 8 using theestablished communications links could re-program one or any number ofcontrollers from a central location, even while "on the fly" (e.g.,while a conveying system is in operation).

Now referring to FIG. 3, there is shown a plan view of a portion of anexemplary conveying system 101 including a multiplicity of modularconveying sections. Each of these modular sections, described furtherbelow, includes a controller 10 that controls the functions of a givenconveying section including the designated task or tasks to be performedfor transporting an article, package or box through the system. Thecontroller 10 of each modular conveying section also is given a uniqueidentification number or address so each section is uniquelyidentifiable.

The illustrated conveying system 101 includes a first section 102, amultiplicity of straight sections 104, a multiplicity of accumulatingsections 106, a multiplicity of index sections 108, an incline/declinesection 110, a diverter section 112, a merge section 114, a spacersection 116 and a corner section 118. A tracking signal generatingdevice 122 is disposed at the front of selected ones of these sections,however, such devices can be disposed at the end of selected ones ofsuch sections. Further, an interconnecting cable/twisted wire 30interconnects each controller 10 thereby establishing a bi-directionalcommunications network for the conveying system 101.

The conveying system 101 also includes a multiplicity of tracking signalgenerating devices 122, each including a roller mechanism that projectsabove the nominal surface of the conveying sections and which isdepressed by the passage of a package, box or article thereover. Thetracking device 122 also includes a sensor that senses the downwardmotion of the roller mechanism and outputs a signal therefor whichindicates the presence of an article/box. The tracking device 122further includes a sensing mechanism to determine the length of thearticle or box passing over the roller mechanism. For example, thesensing mechanism detects the fractional and full rotations of theroller mechanism while it is depressed and equates this to a length.Such a device also is described in copending application Ser. No.08/529,991, the teachings of which are incorporated herein by reference.

The tracking device 122 located in front of the first section 102,determines the length of each package, article or box entering onto theconveying system 101 as well as initiating the tracking process. Otherdevices may be disposed at or along the first section, or at any otherlocations through out the system, for acquiring data or informationconcerning the article. Also, a section following a device may beconfigured to act responsive to signals from the device. For example, asensing device(s) may be provided before a diverter section 112 todetermine the weight or relative weight of the article and/or thearticles overall height, length and width. The diverter section 112 canbe configured to act in a prescribed fashion responsive to the signalsfrom this sensing device. Also, for example a scanning device, such asbar code scanner 124 may be positioned to detect and read bar codelabels affixed to the article being transported. This information couldbe used by the host computer 8 to determine the routing of a package orarticle through the conveying system 101.

The first section 102, each straight section 104, each accumulatingsection 106, each indexing section 108 and each spacer section 116include a plurality of elongated pneumatic lifting assemblies or liftersthat are interleaved with one or more parallel continuously moving beltson which articles are transported. When there are a multiplicity ofsections in series, the belts may be constructed so each belt extendsalong the entire length of the interconnected sections. For example, themoving belts extend between the first section 102 and the corner unit118.

The pneumatic lifting assemblies are used to lift the product orarticles clear of the continuously moving belts. This stops the flow ofthe product or articles passing through a given module or section. Thestoppage of product or articles also is referred to herein as stoppingthe section. The specific manner in which the pneumatic lifters function(i.e., raised, lowered, remain down) is dependent upon the function aparticular section is intended to perform (e.g., accumulation,indexing). The specific fashion in which each of these sections 102-108,116 operate are discussed hereinafter in connection with FIGS. 5A-I.Reference should also be made to U.S. Pat. No. 4,511,030, the teachingsof which are incorporated herein for reference, for further detailsregarding such a conveying section or module.

Each of these sections 102-108, 116 also includes a pneumatic system ofa low and high pressure supply lines, a control valve, air manifold, airbag, and a lifter cup assembly. The controller 10 for each of thesesections 102-108, 116 controls the pneumatics for a given section andthereby control the lifting assembles. In this way, the pneumaticlifters for each section are raised and lowered by the sections'scontroller as required to perform the sections' function.

The diverter section 112 is configured so that boxes or product can beselectively transferred or re-directed in a direction perpendicular tothe direction of the belt line on which the box or product is initiallytraveling. That is one box may continue on straight ahead while anotherbox may be diverted to another line of the conveying system 101. Thecorner section 118 is designed so the box or product is always turned90° with respect to the line of travel. The merge section 114 isdesigned to allow product or articles flowing from two separate lines tobe selectively merged together to flow in a single output line. Thespecific fashion in which each of these sections 112, 114, 118 functionare discussed hereinafter in connection with FIGS. 5A-I.

The diverter section 112, the merge section 114 and corner section 118each include an array of wheels or rollers mounted on a frame. Thewheels or rollers are arranged so the continuously moving belt(s) passfreely through the array. The wheels or rollers of the diverter section112 and the merge section 114 are normally disposed beneath the surfaceof the belts and raised pneumatically when required to change thedirection of the moving product or article. The rollers for the cornerssection 118 are arranged so they always present a contact surfaceslightly higher than the belts. The orientation and shape of the wheelsis adjusted to match the function to be formed. For example, for a mergeunit the rollers are orientated across the belt line. Reference alsoshould be made to U.S. Pat. No. 4,696,386, the teachings of which areincorporated herein by reference.

An incline/decline section 110 is provided to deal with situations whenit is necessary to have the product or articles travel up or down agradient or slope because the belt lines of a portion of the system areat different elevations. For example, to provide a local walkway under aconveying system, the surface of the belt line must be raised orelevated locally. One such incline/decline section that transportsarticles or product up a steep gradient is described in copendingapplication Ser. No. 08/450,006, the teaching of which are incorporatedherein by reference.

The conveying system is arranged so indexing sections 108, precede theincline/decline section 110, the diverter section 112 and the mergesection 114. Using an indexing section 108 with the diverge and mergesections 112,114 assures that articles or product are spaced from eachand that each article or product arrives at a set time on the rollersafter release from an index section. The indexing section 108 alsoavoids the need to provide a separate device, such as photo eye, toactuate the diverge or merge section 112,114. Instead, the controller 10for the diverge or merge section 112,114 may be configured so thesection acts based on the expected arrival time of the product on therollers.

The overall operation of the conveying system 101, the conveyingsections thereof and the controls thereon by the individual controllers10 is best understood from the following discussion. For purposes ofdiscussion, the conveying system shall be assumed to be the baggingconveying system for an airline. However, it shall be understood thatthe conveying system is not limited to the either the illustrated systemor to just an airline bagging handling systems.

As boxes or baggage are received by the first section 102, a bar codescanner 124 scans each piece of baggage to identify the bar code andthereby the information encoded therein. For, example, the bar codelabels would contain information such as the flight number of thedeparting flight.

The information from the bar code scanner 124 is provided to the hostcomputer 8, which determines the routing through the system for each bagreceived. When the presence of a bag on a tracking device 122 isdetected, the controller for the first section 102 gives a uniqueidentifier (e.g., identification number) to the bag and determines fromthe tracking device the overall length of the bag. The data table 200(FIG. 4) for the first section 102 is updated to include theidentification number, the length of the baggage as well as the routinginformation for the bag from the host computer 8.

Each piece of baggage passes through each of the following sections ofthe conveying system 101, including the corner section 118, until theyreach the diverter section 112. As the baggage is past from section tosection, the data tables of the respective sections are updated. For thereceiving section, the data table is updated to include the informationfor each bag entering the section. Correspondingly, the data table 200for the departing section is updated to delete the information for eachdeparting bag. If baggage flow through the section preceding the cornerunit 118 is stopped, then baggage will begin to accumulate on theaccumulator section(s) 106 preceding the corner unit.

If the baggage is being to be routed based on routing information, amessage is sent to the host computer 8 as and when a bag passes throughone of the routing addresses identified in the data table 200. Also,when a bag passes through an identified address, this address is deletedfrom the listing of routing addresses included in the data table.

When the piece of baggage reaches the diverter section 112, itscontroller 10 determines whether to allow the baggage to continue on orto divert it onto a different path. This determination is made based onthe routing information included along with the data table and/or otherpreset criteria programmed into the controller. For example, if the patha bag is to be directed to is full the diverter would not transfer butwould retain the bag on its rollers. As indicated in the foregoing, thepreceding index section 108 controls the flow of baggage to the divertersection 112.

If the baggage continues on (i.e., not diverted), the baggage passesthrough the following sections until it reaches the merge section 114.As described above, the data table for each of these sections is updatedas the baggage successively passes through each section. Depending uponthe merge criteria (e.g., first come first serve) being used, theappropriate preceding index section 108 is actuated to hold up baggagein one line so baggage from the other line passes to the merge section114 and onto the next section. If the baggage is coming from the lineperpendicular to the travel path through the merge section 114, then themerge section rollers also are raised so the baggage is diverted ontothe new travel path.

After passing through the merge section 114, the baggage continues onuntil it reaches the index section 108 preceding the incline/declinesection 110. For purposes of this discussion, the incline/declinesection 110 has article engaging lugs affixed to the travel belt. Assuch, the pieces of baggage are delayed by the index section 108 so eachpiece of luggage will end up between two sets of lugs on the inclinedportion of the incline/decline section 108. The baggage continues totravel on until it reaches the collection point, for example, thearriving baggage carousel within the terminal.

As indicated above, data is stored in the NVRAM 22 of each controllerconcerning each box/article (i.e. product) that is on a given section ofa conveying system 101. An exemplary data table 200 for this informationis shown in FIG. 4. As illustrated, the data table 200 contains anindication 202 of the identification number assigned to the particularbox or article on the section. Further, there is contained a positionindication 204, a length indication 206 and routing tags 208 or sectionaddresses for each item on the data table 200. While three route tags orsection addresses are illustrated, this is not a limitation as there mayany number of routing tags. As also indicated above, the information ordata on the data table 200 for each controller 10 of the conveyingsystem 101 is updated as, and when, articles leave and enter a section.

Preferably, the controller 10 for each section includes the controlroutines for any section type of the conveying system. This simplifiesinstallation and maintenance as well as reduces costs and expenses. Forexample, there is no need to maintain stores of controllers/EEPROMS foreach section type. A flow chart illustrating the basic operations andsteps followed by the communications and control routines of acontroller 10 according to the instant invention are shown in FIGS.5A-I. Reference also should be made to FIGS. 1-4 for the specificcomponents of the controller 10, conveying system 101 and/orcommunications network 100 referred to hereinafter.

As provided herein, the specific control routine, that controls thefunction or operation of a section, is established by the configurationparameters programmed into each controller 10. Further theseconfiguration parameters are under the control of the user and as suchare easily changed in the field. The controller 10 for each conveyingsection is initially programmed with the configuration parametersrequired so the corresponding conveying section functions as intended.As indicated above, these parameters preferably are stored in the NVRAM22 so they are not lost if a power failure occurs. The configurationparameter indicates the functional section type (e.g., spacer, indexsection) as well as other operational parameters, for example, the sizeof the buffer zone used to control the operation of a conveying sectionor module.

Each controller 10 is initially configured or re-configured in one oftwo ways. The host computer 8, using the communications networkestablished between each controller of the conveying system, establishesa communications link with each controller. Using this link, thecomputer programs in the appropriate configuration parameters.Alternatively, a terminal or computer is connected to the RS232 I/O port20 of each controller 10 and each controller is programmed with theinitial configuration parameters.

After each controller 10 is initially configured the conveying system ispowered up and the transport of product, articles, boxes, through eachsection of the conveying system is started, step 1000. Thereafter, eachcontroller 10 of a conveying system 101 performs a number of functionsin parallel. In particular, each controller 10 evaluates all messages itreceives and implements the specific control routine(s) of theapplications program so the corresponding conveying sections functionsas intended (e.g., functions as an index section). That is, the presentsection controller performs its communications protocol routinesindependently of its function specific control routine(s). It should berecognized that while the following may show or describe steps oroperations in series or in parallel, it is within the scope of thepresent invention for the steps to be performed in different sequencesthan that illustrated and described herein.

For purposes of the following discussion the terms present section,prior/previous section(s) and next section(s) are used to distinguishdifferent conveying sections of a portion of the conveying system 101.The present section is any of the sections comprising the conveyingsystem 101, however, in the following the term is generally used toidentify the section(s) of a conveying system that perform the specificcontrol routine being described. Prior/previous section(s) is used toidentify the section(s) immediately preceding the present section. Nextsection(s) identifies the section(s) that immediately follow the presentsection.

When performing its communications or message processing functions, thecontroller 10 of the present section evaluates all messages beingreceived over the bi-directional communications network 100.Additionally, the present section controller 10 determines if a messagebeing received is for the present section controller or for anothercontroller, step 1002. If the message is not for the present controller(NO) then the message is sent onto the next or previous controller andthe process returns to the beginning of the communications controlroutine, step 1002.

If a received message is for the present section controller (YES, step1002), then the controller evaluates the message to determine if it is aprogramming message, step 1004. As noted above, any or all of thecontrollers 10 of a conveying system 101 may be accessed by the hostcomputer 8 to initially set or to alter the controller's configurationparameters. For example, the configuration parameters may have to bechanged when there is change in the physical layout or arrangement ofthe conveying system. If it is such a message (YES) then the processproceeds to step 1800, FIG. 5I.

If it is not a programming message (NO, step 1004), then the presentsection controller evaluates the received message to see if it is a stopmessage/command, step 1006. A stop message or stop command is sent bythe next section controller to the present section controller andgenerally indicates that the next section is stopped. That is, flow ofproduct (e.g., boxes, articles, packages) was stopped in the nextsection. The stop message from the next section typically is the resultof stop messages from the controllers downstream of the next section.

If it is a stop message (YES, step 1006) then the present sectioncontroller sets a stop flag, step 1008. The status of the stop flag isevaluated by the function specific control routines, discussedhereinafter, for each section type. In general, these function specificcontrol routines determine when, and if, the flow of product also shouldbe stopped in the present section. After setting the stop flag, theprocess returns to the beginning of the communications protocol, step1002.

If it is not a stop message (NO, step 1006), then the present sectioncontroller evaluates the message to see if it is an indexing message,step 1010. An indexing message is sent by the next section controllerwhen the next section is not stopped, or is no longer stopped, and thuscan accept product from the present section. If it is an indexingmessage (YES), then the stop flag of the present section is cleared,step 1012 and the process returns to the beginning of the communicationsprotocol, step 1002.

If it is not an indexing message (NO, step 1010), then the presentsection controller determines if the message received is a data inquirymessage, step 1014. The host computer 8, using the bi-directionalcommunications network 100 of the controllers, can send out a messagethat requests one, all or any combination of controllers to output adata message. If it is a data inquiry message (YES) then the presentsection determines if a reply is required, step 1015. If a reply isrequired (YES, step 1015), then the present section controller 10 sendsa message to the host computer 8 using the bi-directional communicationsnetwork of the controllers, steps 1016, 1022.

For example, the host computer 8 could send out an inquiry message toall controllers of the conveying system 101 requesting the location(s)of a specific package(s). The controller 10 for each section wouldevaluate its data table to determine if the package(s) are located onits section. If yes, the controller would send the appropriate replyback to the host computer 8 via the bi-directional communicationsnetwork 100. After sending the message, or if no reply is required (NO,step 1015), the process returns to the beginning of the communicationsprotocol, step 1002.

If it is not a data inquiry message, (NO, step 1014), then thecontroller 10 determines if the received message is an emergency stopmessage, step 1018. If YES, then the present section is stopped and anemergency stop message is sent to the next and previous sections, steps1020, 1022. The process then returns to the beginning of thecommunications protocol, step 1002.

Each controller 10 includes a normally closed switch 27 that can beactuated by an individual to stop the operation of a given section. Whenthis switch is actuated (e.g., opened), the present section controller10 stops the present section and outputs an emergency stop message tothe other sections comprising the conveying system so system operationalso is stopped. This is done to protect or minimize injury to others aswell as to minimize or avoid damage to the system, system componentsand/or packages in transit.

As indicated above, the controller 10 when the conveying process isstarted, step 1000 determines from the configuration parameters thesection type for the present section. Specifically, the controllerdetermines if the present section is to be operated as a first orstraight section, step 1030; as an indexing section, step 1032; as adiverter section, step 1034; as a merge section, step 1036; as a spacersection, step 1038; or as an accumulation section, step 1040.Thereafter, the present section controller 10 implements the specificcontrol routine(s) applicable for the section type established by theconfiguration parameters.

The straight, indexing, spacer and accumulating sections 102-108, 116mechanically are the same conveying section module and differ only inthe way in which the control routine operates the conveying sectionmodule. As such, these section types can be easily changed from onesection type to another (e.g. from straight to accumulating) by changingthe appropriate configuration parameters programmed into the controller.Also, the diverter and merge sections 112,114 can be programmed so as tooperate in a different fashion by means of changing the configurationparameters. For example, a diverter or merge section 112,114 can beconfigured so it passes articles straight through the section (e.g. nodiversion) or so the articles always are turned through 90° to thetravel path (i.e., section functions as a corner).

This capability allows the user to alter the functional arrangement of aconveying system 101 without requiring hardware changes to individualsections or altering the physical arrangement of the conveying system.Thus, a conveying system of the instant invention can be easilyconfigured to operate temporarily in one fashion and then returned toits normal system functional arrangement simply by reprogramming theconfiguration parameters of affected controllers.

Referring next to FIG. 5B, there is shown the control routine of acontroller 10 when configured so a section of the conveying system 101functions as a straight section 104, (YES, step 1030, FIG. 5A). Astraight section 104 is provided in a conveying system 101 so goodsreceived at one end of the section or module are transported to theother end and onto the next section in the system. The section runscontinuously, until the section's controller 10 determines that it mustbe stopped i.e. flow of goods in transit stopped). Further, thecontroller of the straight section 104 also assures that information ofthe goods in transit is provided to the next section. A straight sectionis the first section 102 of the conveying system.

In operation, the present section controller 10 (i.e. the controller fora straight or first section 104,102) determines if the stop flag hasbeen set, step 1100 (FIG. 5B) in response to the receipt of a stopmessage from another controller (FIG. 5A, steps 1006, 1008). If the stopflag is set (YES), the present section controller 10 evaluates thelocation of the articles in transit on the present section to determineif there is an article located in the buffer zone at the end of thepresent section, step 1102. The buffer zone typically is defined so theforward momentum of the article being stopped does not cause the articleto pass onto the next section.

If an article is located in the buffer zone (YES), the present sectioncontroller stops the present section, step 1104. The present sectioncontroller also sends a ready message to the next section controller,step 1106, step 1022 (FIG. 5A). If the present section is not the firstsection 102, the present section controller also sends a stop message tothe prior section, step 1106. The ready message is an indication to thenext section that an article is ready to be transferred to the nextsection. The stop message provides an indication to the prior sectionthat the present section cannot accept any further goods. The controllerfor the prior section determines if, and under what circumstances, theprior section should be stopped.

If the stop flag is not set (NO, step 1100) or there is no article inthe buffer zone when the stop flag is set (NO, step 1102), then thepresent section controller performs two functions as and when calledupon. Specifically, the present section controller controls the entry ofgoods onto the present section and controls the passage of goods throughthe present section and onto the next section.

Preferably, the conveying system 101 is configured with a trackingdevice 122 at the front end of the present section to provide a positiveindication of the arrival of goods (e.g., box, article) at the section'sfront end. When a new article is sensed by the tracking device 122(e.g., roller mechanism is depressed), the present section controllerdetects a new box, article or product, step 1110. If the present sectionis a first section of a conveying system (YES, step 1112), then thepresent section controller assigns a unique identification tag or numberto the box, step 1114. Using the tracking device 122, or other lengthmeasuring means known in the art, the present section controller 10 alsodetermines the length of the new box, step 1116.

As noted above, a conveying system and its controllers also can beconfigured to route the boxes or articles about the system in apredetermined fashion. Thus, if a box/article is to be routed around thesystem (YES, step 1118), the host computer 8 provides the desired routetags to the present section controller, step 1120. The route tagsgenerally identify the address of a section at which some action is tobe taken relative to routing. For example, when the box arrives at thediverter section corresponding to a specified address or identificationnumber, then the box would be directed to proceed along one of the twooutgoing lines according to the routing instructions.

After obtaining the routing information (step 1120), or if the box isnot to be routed (NO, step 1118), the data table 200 for the presentsection controller is updated, step 1122 to include the information forthe new box/article. This includes the identification number 202, length206 and, when applicable, the route tags 208. The process then returnsto the beginning of the control routine for the present section, namelyto determine if the stop flag is set, step 1100. The data table 200 alsoincludes an identifier 210 or address for the present section.

If the present section is not the first section of the conveying system(NO, step 1112), then the present section controller acquiresinformation from the prior section, step 1130. In particular informationregarding the length of the next box/article to arrive. The presentsection controller based on the location of the articles/boxes on thesection determines the room available on the present section to receivethe next box/article to arrive. The present section controller thendetermines if there is room on the present section to take the nextbox/article to arrive, step 1132. If there is (YES), then the next boxto arrive is transferred from the prior section to the present section,step 1134. This is accomplished by the controller of the present andprior sections transmitting index and ready messages to each other andallowing the box/article to continue moving along with the moving belts.The present section controller also updates its data table 200 with thedata/information for the box that just arrived, step 1122.

After each box enters onto the present section, whether it is the firstor a straight section, the present section controller also starts anelapsed travel time tracking process, step 1700 (FIG. 5H). Using thisprocess, the present section controller keeps track of the elapsed timefrom entry of each box/article on the present section. This is used as ameans for determining if any box/article did not arrive at the end ofthe present section and thus removed from the present section. In thisway, the present section controller can determine if a box/article wasremoved from the present section. For further details concerning thistime out tracking process, reference should be made to the discussionbelow regarding FIG. 5H.

If there is insufficient room on the present section to receive the nextbox/article to arrive (NO, step 1132), then the present sectioncontroller sends a stop message to the prior section and a ready messageto the next section, steps 1136, 1022 (FIG. 5A). After determining thereis insufficient room (NO, step 1132) or after updating the data table(step 1122), the process returns to the beginning of the control routinefor the present section, step 1100.

As noted above, the present section controller 10 controls the passageof goods through the present section and onto the next section. Whileddoing this, the present section controller continuously evaluates thelocation of boxes/articles in transit on the present section, step 1140.The present controller also, as it determines the location of theboxes/articles in transit, causes the locational information in thepresent section data table 200 to be updated accordingly.

The present section controller 10 evaluates the locational informationto determine if an in-transit box/article is located in the buffer zone,step 1142. This buffer zone determination is preferably done bycomparing the time that has elapsed since the box entered the presentsection with the time required to traverse the present section. Thetraversal time is adjusted by the present section controller to accountfor transport delays such as when stopping the present section. If thepresent section controller determines that the leading edge of thebox/article is in the buffer zone (YES) then the controller sends out aready message to the next section to indicate that a box is availablefor transfer, steps 1144, 1022 (FIG. 5A).

The present and next sections communicate with each other following theready message transmission to determine if there is room on the nextsection for the box/article to be transferred, step 1146. Similar to theabove described present section available room determination of step1132, the next section determines if there is room available on the nextsection is sufficient to handle the length of the box/article, step1146. If there is sufficient room (YES), then the box is sent to thenext section and information from the present section data table iscommunicated to the next section for inclusion in the next section datatable, step 1148. The present section data table also is updated todelete the information, when the box/article is transferred, step 1122.It should be noted that there may be other section specific criteriathat preclude the next section from taking the box/article form thepresent section even though there physically may be sufficient room atthe front end of the next section (e.g., box in next section bufferzone).

If there are boxes/articles in the conveying system be routed by meansof route tags 208 in the data table 200, then the present sectioncontroller also evaluates the routing tags to determine if the presentsection is one of the section addresses identified as being a routingtag. If yes, then the present section controller sends a message back tothe host computer 8 to indicate that the box/article has passed througha tagged location/address. Also, when the next section data table isupdated the address of the present section is not included with thelisting of routing tags or addresses (i.e., present section addressremoved from listing). Thus, the number of routing tags listed andtracked is reduced as the box/article successively passes through eachidentified section address.

If there is insufficient room on the next section to receive thebox/article from the present section (NO, step 1146), then the presentsection controller stops the present section, step 1150 (i.e stops flowof boxes/articles). Also, the present section controller 10 sends aready message to the next section, step 1152 & step 1022 (FIG. 5A). Ifthe present section is not the first section 102 of a conveying system,then the present section controller also sends a stop message to theprior section. After stopping the present section, the process thenreturns to the beginning of the control routine for the present section,step 1002.

Referring next to FIG. 5C, there is shown the control routine of acontroller when configured so a section of the conveying system, thepresent section, functions as an indexing section 108 (YES, step 1032,FIG. 5A). There are a number of conveying sections, such as theincline/decline, diverter and merge sections 110, 112, 114, where properoperation of that conveying section involves controlling or timing theentry of a box/article onto that section. The index section operates asa stop and go type of section, where a box is stopped and then sent onto the next section when it is appropriate. In this way, the downstreamsection/module operates properly, thereby minimizing the potential fordamage to the boxes on the conveying system as well as to the individualsections of the system.

In operation, the present section controller 10 determines if the stopflag has been set, step 1200. If the stop flag is set (YES), then thecontroller evaluates the location of the articles in transit on thepresent section to determine if there is an article located in thebuffer zone at the end of the present section, step 1202. If an articleis located in the buffer zone (YES), then the present section controllerstops the present section, step 1204. It should be noted, this is doneirrespective of the indexing criteria for the present section. Also, thepresent section controller sends a ready and stop messages respectivelyto the next and prior sections, step 1206 & step 1022 (FIG. 5A). Afterstopping the present section, the process returns to the beginning ofthe control routine for the present section, step 1200.

If the stop flag is not set (NO, step 1200) or there is no article inthe buffer zone when the stop flag is set (NO, step 1202), then thepresent section controller performs three functions as and when calledupon. Specifically, the present section controller controls the entry ofgoods onto the present section, controls the stopping of in-transitgoods at preselected locations of the present section and controls therelease of the stopped goods onto the next section.

As provided in the foregoing, the conveying system 101 preferably isconfigured with a tracking device 122 at the front end of the presentsection to provide a positive indication of the arrival of goods (e.g.,box, article) at the section's front end. Thus, the present sectioncontroller 10 monitors the tracking device and/or outputs signals fromthe prior section (e.g., a ready message) for purposes of determiningthe presence of a box/article next to arrive, step 1210. If a newbox/article is ready for transfer (YES), then the present sectioncontroller acquires information from the prior section, step 1212. Inparticular information regarding the length of the next box/article toarrive.

The present section controller, as described above, determines the roomavailable on the present section and whether the available room issufficient for the next box/article to arrive, step 1214. If there issufficient room (YES), then the box/article is transferred from theprior section to the present section, step 1216 and the data table 200for the present section is updated with the data/information for thatbox/article, step 1218. The present section controller also starts anelapsed travel time tracking process, step 1700 (FIG. 5H) followingreceipt of the box/article that is discussed below.

If there is insufficient room on the present section to receive the nextbox/article to arrive (NO, step 1214), then the present sectioncontroller sends stop and ready messages respectively to the prior andnext sections, step 1220 & step 1022 (FIG. 5A). After determining theavailable room is insufficient (NO, step 1220) or after updating thedata table (step 1218), the process returns to the beginning of thecontrol routine for the present section, step 1200.

As indicated above, the present section controller 10 also determines ifthe motion of a box/article along the present section should be stoppedfor indexing, step 1230. Typically, when a box on the present section isdetermined to have arrived at a set location, an indexing location, thebox is stopped unless the next section is ready to receive it. Theindexing location is a variable that is programmed by the user for agiven application. For example, the end of an index section (i.e., thebuffer zone) or some other intermediate location could be specified asthe indexing location. If the motion of the box(es) on the presentsection should continue, (NO, step 1230) then the process returns to thebeginning of the control routine for the present section, step 1200.

The box in transit can be stopped at an indexing location based on usingany of a number of criteria or methods. For example, the present sectioncontroller could be configured so the present section is stopped after apresent count of boxes passes through the section. The present sectionalso could be stopped based on tracking information (e.g., routinginformation) in the data table or based on a switch input (e.g.,photo-eye). If a box/article should be stopped at an indexing location(YES, step 1230), then the controller stops the present section, step1232. As indicated above, stopping a section involves lifting thesection's plurality of elongated pneumatic lifting assemblies so thebox(es) on the section are lifted out of contact from the movingbelt(s).

The present section, using the bi-directional communications link withthe prior section, also sends a stop message to the prior section, step1234. The prior section using the control routine specific to it,determines if and when to stop the prior section. After stopping thepresent section, the process returns to the beginning of the controlroutine for the present section (i.e., step 1200).

If a box/article is already stopped at an indexing location, as a resultof steps 1230, 1232, then the present section controller determines ifit is time to release the box/article to the next section, step 1240.There are a number of techniques that can be used to determine when abox should be released and which are typically dependent upon the typeof section or module which follows the present section. For example,when the present section precedes an incline/decline section 110, thepackage is released from the indexing location so it will arrive on theincline section between two sets of lugs.

The present section controller 10 also can be configured to beresponsive to actuation signals from manually operated switches. Thus,when a manual switch is activated, the box is released to the nextsection. For example, an indexing location can conform to the workstation of an individual. Thus, after the work is performed, the workerwould actuate a switch so the article would be released so it can travelto the next work station and/or next section. The present sectioncontroller 10 also can be configured to release an article/box afterreceiving an actuation signal from a manual switch and an actuationsignal from another release control mechanism (e.g., timer). Further,while a single indexing location per section is described, a controllercan be configured so a section includes a plurality of such indexinglocations.

In sum, an article held up on an indexing section may be releasedmanually and/or automatically. The article may be released automaticallybased on elapsed time, count, and ready signals from the next section.It should be recognized that the release criteria described herein isexemplary and any criteria or technique consistent with the intent andpurpose of the present invention may be used.

If the box or article should be released to the next section (YES, step1240), then the present section is started, step 1242. As indicatedabove starting a section involves lowering the elongated liftingassemblies so the article(s)/box(es) on the present section contact themoving belt. The article/box is then transferred onto the next sectionand the data table 200 of the present section is updated (i.e., deletinginformation concerning the transferred box), steps 1244, 1246.

If the address of the present section is one of the specified route tags208, then the present section controller 10 also sends out a message tothe host computer 8 indicating the article has passed through aspecified route tag, step 1248, step 1022 (FIG. 5A). Thereafter, theprocess returns to the beginning of the control routine for the indexsection, step 1200.

Referring next to FIG. 5D, there is shown the control routine of acontroller 10 when configured so a section of the conveying system, thepresent section, functions as a spacer section 116 (YES, step 1038, FIG.5A). In conveying systems, the in-transit boxes/articles preferably arespaced from each other to avoid damage to the boxes/articles as theymove through the system. Spacing of boxes/articles also allows them tobe clearly diverted or merged by a diverter on merge section. Separationalso makes it easier to identify a box/article as it passes over atracking device. The spacer section 116 is a stop and go type of sectionthat controls the spacing of boxes/articles as they are passed onto thenext section. Preferably, the spacing provided by a spacer section isadjustable by the user.

As similarly described above for an index section 108 (i.e., see FIG.5C), in operation the present section controller determines if the stopflag is set, step 1300 and, if so (YES), whether a box/article is in thebuffer zone, step 1302. If an article is located in the buffer zone(YES), then the present section controller stops the present section,step 1304 and outputs ready and stop messages respectively to the nextand prior sections step 1306 & step 1022 (FIG. 5A). After the presentsection is stopped (step 1304), the process returns to the beginning ofthe control routine for the present section, step 1300.

If the stop flag is not set (NO, step 1300) or there is no article inthe buffer zone when the stop flag is set (NO, step 1302), then thepresent section controller 10 performs two functions as and when calledupon. Specifically, the present section controller 10 controls the entryof goods onto the present section and it controls the release of thegoods onto the next section so they are spaced from each other.

As described in the foregoing discussion concerning FIG. 5C, a trackingdevice 122 preferably is located at the front of the present section toprovide a positive indication of a box/article being at the section'sfront end. Also as described in the foregoing, the present sectioncontroller 10 monitors for the presence of a box/article at the frontend (step 1310), acquires information regarding the box/article to betransferred (step 1312) and determines if there is room on the presentsection for the box/article (step 1314).

If there is sufficient room (YES, step 1314), then the box/article isaccepted (step 1316), the present section data table is updated (step1318) and the elapsed travel time tracking process is started, step 1700(FIG. 5H). If there is insufficient room (NO, step 1314), then thepresent section controller sends stop and ready messages respectively tothe prior section and next sections, step 1320 & step 1022 (FIG. 5A).After determining there is insufficient room or after updating the datatable (steps 1314, 1318), the process returns to the beginning of thecontrol routine for the present section, step 1300.

For the box spacing process, the present section controller determinesif a box is ready to leave the section, step 1330. Preferably, atracking device 122 is located between the present and next sections, sothere is a positive indication of the presence of a box at the end ofthe present section. That is the tracking device outputs a box presentsignal to the controllers of the present and next sections. However, thepresent section controller also can determine if the box is at the endof the present section based on the elapsed travel time of the box onthe present section. If there is no box located at the end of thepresent section (NO, step 1330) then the process returns to thebeginning of the control routine for the present section, step 1300.

If a box is located at the end of the present section (YES, step 1330),then the present section continues to run for a user set time T₁, afirst time interval, steps 1332,1334. This ensures that most of the boxhas traveled off the lifting assembly of the present section and ontothe dead zone between the present and next sections. Alternatively, thepresent section controller can determine a first time interval T₁ foreach box/article by using the stored length of the box/article and thetravel speed of the belts.

When the first time interval T₁ is exceeded (YES, step 1332), thepresent section controller stops the present section, step 1336 whilethe next section continues to run. The present section remains stopped,until after the box is determined to have left the present section, step1338 and until after an additional time period, a second time intervalT₂ is determined to have elapsed, step 1340. After the second timeinterval T₂ has elapsed (YES, step 1340), the present section isre-started, step 1342 by lowering of the section's lifting assemblies.In this way, the boxes going onto the next section are spaced from eachother.

Further, the data table 200 of the present section is updated bydeleting the information concerning the box that left, step 1344. Asalso discussed in the foregoing, if the present section is one of theidentified addresses for a route tag, then the present sectioncontroller 10 also sends a message back to the host computer 8 that thebox has passed therethrough. Thereafter, the process returns to thebeginning of the control routine for the present section, step 1300.

When a tracking device 122 is located between the present and nextsections, the present section controller 10 determines the box has leftthe present section when it loses the box present signal from thetracking device. The first and second time intervals are user setparameters, where the second time interval can be in the range of zeroto the time for traveling the length of the present section.

Referring next to FIG. 5E, there is shown the section control routinewhen the programmed configuration parameters configure the controller 10so the present section functions as an accumulation section 106 (YES,step 1040, FIG. 5A). A conveying system is commonly required toaccumulate product moving therethrough at various points along thelength of the system. The reasons for doing this include accommodatingfor consistent throughput for an automated process and/or accommodatingfor the peaks and troughs of product throughput. Generally, thisinvolves temporary storage of product, for example, during the peaks,which is then released progressively when allowed.

For an accumulating section of the instant invention, the section runscontinuously, until its controller 10 determines that the section shouldbe operated in one of its pre-programmed accumulation modes.Accumulation of product is accomplished by lifting the product clear ofthe continuously moving belts, using the elongated lifting assemblies,thereby stopping movement of the product (i.e., also referred to asstopping the present section). In a one embodiment, the control routinefor the controller 10 of an accumulation section includes three basicand user selectable modes to control the accumulation and movement ofproduct.

In operation, the present section controller 10 determines if the stopflag has been set, step 1400. If the stop flag is not set (NO), then thecontroller determines if the present section is to operate in the thirdaccumulation mode, step 1402. If not configured for operation in thethird accumulation mode (NO), then the present section controlleraccepts the box next to be received, step 1404 and updates its datatable 200, step 1406. In this condition, the present section controllerfunctions similar to a straight section in passing through product andtransferring it onto the next section.

If the present section controller is configured to operate in the thirdaccumulation mode (YES, step 1402), then the controller determines ifthe first box/article on the section is within the buffer distance setfor the present section, step 1408. If yes (YES), then the presentsection continues to run as well as accepting product (step 1404) andupdating the data table (step 1406). If the first box is outside the setbuffer distance (NO, step 1408), then the present section controllersends a stop message to the prior section, step 1426 & step 1022 (FIG.5A) and returns the process to the beginning of the control routine,step 1400. Although a stop message is transmitted to the prior section,the present section continues to run so product thereon can betransferred onto the next section.

If the stop flag is set (YES, step 1400) indicating that the nextsection is stopped, then the present section controller stops thepresent section, step 1410 and identifies which accumulation mode (e.g.,modes 1-3) the present section is to emulate, step 1412. Based on theoperating mode determined by the foregoing steps 1402, 1412, the presentsection controller 10 determines if it has current information regardingthe box/article next to arrive from the prior section, step 1414. If not(NO), the present section controller acquires the information from theprior section using the bi-directional communications link between thesections, step 1416.

If the present section has current information (YES, step 1414) or hasacquired the information (step 1416), the controller determines if thereis sufficient room on the present section to accumulate the nextarriving box/article, step 1418. If there is sufficient room (YES), thenthe present section controller 10 operates the present section so as toaccumulates product onto the present section, step 1422. The presentsection controller also causes its data table 200 to be updated withinformation concerning the box/article added thereto, step 1424. Thepresent section controller also starts the elapsed travel time trackingprocess, step 1700 (FIG. 5H) following receipt of the box/article.

If there is insufficient room on the present section to receive the nextbox/article to arrive (NO, step 1418), then the present sectioncontroller sends stop and ready messages respectively to the prior andnext sections, step 1426 & step 1022 (FIG. 5A). After determining thereis insufficient room (NO, step 1418) or after updating the data table(steps 1406,1424), the process returns to the beginning of the controlroutine for the present section, step 1400.

The following describes the process followed by the present sectioncontroller for each of the three accumulation modes of the presentsection. In two of the operating modes, the present section runscontinuously, transporting product from one end of the section to theother. When the stop command of the next section is received by thepresent section (i.e., stop flag set), the present section immediatelystops and the control routine begins to accumulate product on thepresent section. In the third operating mode accumulation actions aretaken by the present section controller to prevent large gaps betweenboxes/articles on the present and prior sections.

For one operating mode, when the present section is put into theaccumulation mode after receiving a stop message from the next section,its controller checks for available space ahead of the box/article (i.e.first box) closest to the next section. The available space isdetermined from the following relationship, where B is the length of thepresent section, P₁ is the distance between the front of the presentsection and the leading edge of the first box, and S, a user setparameter, represents product spacing.

AVAILABLE SPACE=B-(P₁ +S)

The present section controller 10 using information about the productnext to receive, determines whether or not the present section has roomto accept the next product. If the present section controller does nothave this information initially, it obtains this information from theprior section using the bi-directional communications link between thesections. The next product from the prior section is accepted if thelength of the next product plus product spacing ("S" distance) is lessthan or equal to the available space.

If the product cannot be accepted from the prior section, then thepresent section remains stopped, a READY message is communicated to thenext section and an STOP message is sent to the prior section. Asproduct is transferred to the next section, the present sectioncontroller re-evaluates the space available on the present section andre-determines whether product can be accepted.

If the product on the prior section can be accepted by the presentsection, an INDEX message is sent to the prior section. The presentsection remains stopped until it receives a signal from the priorsection indicating that a product is about to arrive at the presentsection such as that described above for a spacer section. When thepresent section receives this signal, it begins to run and continuesrunning for a set time interval. The set time interval puts a sets spacebetween the product on the present section (i.e., the "S" distance).After the time interval elapses, the present section is again stopped.

In a second operating mode, once the present section is put into theaccumulation mode following receipt of the stop message, the presentsection controller checks for the total unoccupied length on the presentsection. The unoccupied length is determined from the followingrelationship, where B is the length of the present section, L_(i) is thelength of each box/product con the present section (i.e., the "firstbox"), and S, a user set parameter, that represents product spacing.

UNOCCUPIED LENGTH=B-Σ(L_(i) +S)

As described in the foregoing, the present section controller 10 usinginformation about the product next to be received, determines whether ornot the present section has room to accept the next product. The nextproduct from the prior section is accepted if the length of the nextproduct plus product spacing ("S" distance) is less than or equal to thetotal unoccupied length.

If the product cannot be accepted from the prior section, then thepresent section remains stopped, a READY message is communicated to thenext section and an STOP message is sent to the prior section. Asproduct is transferred to the next section, the present sectioncontroller re-evaluates the space available on the present section andre-determines whether product can be accepted from the prior section.

If the product on the prior section can be accepted by the presentsection, an INDEX message is sent to the prior section. The presentsection remains stopped until it receives a signal from the priorsection indicating that a product is about to arrive at the presentsection such as that described above for a spacer section. When thepresent section receives this signal, it begins to run in the "thumper"mode where the product to be received is indexed onto the presentsection.

In the thumper mode, the controller 10 controls the lifting assembliesso they are inflated and deflated to cause a pulsing action. The pulsingaction is designed to gently close the gap between product and also toprevent damage to the underside of the product. The on/off time of thepulsing action is set by the user and can be optimally set for theproduct traveling on the conveying system.

In contrast to the first operating mode, product is accumulated on thepresent section in the second operating mode until the controllerdetermines the present section is essentially full. That is, the totalunoccupied space on the present section is essentially zero or less thanthat required to accept the next product from the previous section. Inthe thumper mode, if product reaches the end of the present sectionbefore the section is full the forward motion of the product closest tothe next section is stopped by the raised lifting assemblies of the nextsection. This allows the present section to be filled to capacity.

The present section runs in the thumper mode until a set time interval,representative of the distance between product ("S" distance) haselapsed after the product has left the previous section. The set timeinterval puts a sets space between the product on the present section(i.e., the "S" distance). After the time interval elapses, the presentsection is again stopped. Reference should be made to the foregoingdiscussion regarding the first accumulation operating mode for detailsregarding the transfer of product to the next section which is equallyapplicable to a controller using the thumper accumulation mode.

In the third operating mode, the present section controller isconfigured to evaluate the boxes/articles on the present section todetermine if the first box/article is located inside a preset bufferdistance from the beginning or front of the present section. If abox/article is located inside the buffer distance then the sectioncontinues to run and the process of accepting boxes from the priorsection will continue (e.g. INDEX message will be sent to priorsection). When the box/article moves outside the buffer distance, thenpresent section continues to run. However, a stop message is sent to theprior section so as not to allow any more boxes/articles to move ontothe present section. In this way, the present section controllerprevents large gaps between boxes that cannot be closed up if and whenthe present section goes into accumulation. When this box goes onto thenext section, the present section sends an index message to the priorsection. Thus, the process of transferring product from the priorsection to present section is re-started.

As with the other operating modes, when the present section controllerreceives a stop message from the next section the present section isstopped. Thereafter, the present section controller functions like thefirst above described operating mode.

When in the accumulation mode product is transferred from the presentsection to the next section, when the next section can receive anotherbox/article and there is room on the next section for the box/articleready for transfer. As such, the present section controller monitors thebi-directional communications link for messages (i.e., INDEX messages)indicating that the first box in the present section can be released,step 1430. If the box/article is releasable (YES) then the next sectiondetermines whether there is sufficient room for the box/article to betransferred to the next based on information obtained from the presentsection data table, step 1432.

If there is sufficient room (YES, step 1432), then the present sectioncontroller causes the box/article to be sent onto the next section andcauses the information relating thereto to be communicated to the nextsection controller, step 1434. Further, the present section controlleralso causes the present section data table to be updated (i.e., todelete the related information), step 1436. Thereafter, as well as whenthere is insufficient room (NO, step 1432) or the box/article cannot bereleased (NO, step 1430), the process returns to the beginning of thecontrol routine for the present section (step 1400).

Preferably, the present section controller also controls the transfer ofproduct so the boxes/articles being transferred onto the next sectionare spaced from each other. The spacing function performed is similar tothat performed by a spacer section. Specifically, the present sectionruns until a preset time interval T₁ has elapsed after the presentsection controller receives a "box present" signal from a trackingdevice 122 between the two sections. This ensures that most of theproduct has travelled off the prior section and onto the "dead zone"between the two sections. The present section is stopped while the nextsection continues to run thereby spacing the product out on the nextsection. After an second time interval T₂ has elapsed following theproduct leaving the section, the signal preventing the present sectionfrom running is removed.

Referring next to FIG. 5F, there is shown the section control routinewhen the programmed configuration parameters configure the controller 10so the present section functions as a diverter section 112 (YES, step1034, FIG. 5A). For the conveying system of the instant invention,product traveling along one line can be distributed into two lines usinga diverter section 112 applying one of any number of sorting/divertingcriteria. For example, the controller of the diverter section 112 can beconfigured to distribute the product based on routing information (i.e.,the route tags), the length of the product based on data table input,switch input based on an evaluation of some other physicalcharacteristic of the product (i.e, height, width, weight) and based oncount (e.g., divert every other box). The controller 10 of the divertersection 112 also may be configured to operate in a specified fashion ifone of the output lines is blocked/full.

The diverter section 112 includes a plurality of rollers that aremounted on a frame which can be selectively raised or lowered. When theframe is raised, the rollers lift the product off the moving belts andact on the product so as to cause it to change its direction of flow ormovement. For example, the rollers cause, the product to make a 90° leftturn with respect to the original direction of flow. When the frame islowered, the rollers are disposed below the surface of the moving belts.As such, the product remains in contact with the moving belts and passesthrough the diverter section 112. As such, in one arrangement productpasses through the diverter section 112 to one of the output lines andin another arrangement, the diverter's rollers causes the product tochange direction so it enters another line.

Preferably, the diverter section 112 is preceded by an index section 108as illustrated in FIG. 3. The index section 108 is used to control thearrival time of the product on the diverter section. As such, thediverter section 112 preferably is actuated on the expected arrival timeof the product. Alternatively, the preceding section may be configuredwith a sensing mechanism, such a photoelectric eye, that actuates thediverter section after a preset time delay has elapsed. The precedingsection also is operated to hold or retain the product thereon, when thediverter section 112 cannot accept the product next to arrive.

In operation, the present section controller 10 (i.e., the controllerfor the diverter section) determines if it has current information aboutthe next product to arrive, step 1500. If not (NO), then the presentsection obtains this information from the prior section using thebi-directional communications link between the sections, step 1502.Thereafter, the controller 10 performs a status check to see if there isproduct already being diverted, that is, is there product already on thepresent section 112, step 1504. The present section controller 10 alsochecks to see if both of the output lines are full. Alternatively, thepresent section controller 10 can be configured so it checks the outputline for the next product to arrive to see if this line is full.Typically this is accomplished by determining if stop messages had beenpreviously communicated to the present section controller 10 by thecontrollers for the next sections.

If no product is being diverted, and/or the output lines are not full,(NO, step 1504) then the present section accepts the product next toarrive from the prior section, step 1506. The present section controller10 also causes the present section data table to be updated with theinformation concerning the accepted product, step 1508.

If there is product on the present section, and/or both output lines arefull (YES, step 1504), then the present section controller 10 sends astop message to the prior section, step 1520 & step 1022 (FIG. 5A).Thereafter, the process returns to the beginning of the section specificfunctional control routine, step 1500. As indicated above, the priorsection is operated so it is stopped and the product is held thereon,when a stop message is sent by the present section controller 10. It iswithin the skill of one knowledgeable in the art, to appropriatelyconfigure the present section controller 10 for use with other divertermechanisms or methodologies.

If product can be accepted (YES, step 1506), then the present sectioncontroller 10 determines the routing requirement for the product next toarrive, step 1510. Specifically, the present section controller 10determines if the product is to be diverted or passed through thepresent section to the appropriate output line. If the product next toarrive, is to be diverted (YES), then the present section controller 10determines if the divert output line is full, step 1512. This isaccomplished using the bi-directional communication links establishedbetween the controllers of the present section and the next section inthe divert output line.

If the divert output line is not full (YES), then the controller 10configures the present section (i.e., raise rollers) at the appropriatetime, step 1514. The product is then transferred to the divert outputline, step 1516. The present section remains running in the configuredarrangement for a set time interval "s" after the product left the priorsection. Once the time interval has expired, the process returns to thebeginning of the control routine (step 1500). Typically, the presentsection also is operated so the rollers remain disposed below thesurface of the moving belts except when the product is to be redirectedinto the divert output line.

A conveying system typically is arranged to include a path forrecirculating product back to the beginning of a diverter section sosystem operation is not adversely affected (i.e., stopped) if the divertoutput line is temporarily full. In these situations, the product ispassed straight through a diverter section. As such, the present sectioncontroller 10 includes an override diversion criteria that forces theproduct to be routed in a specific manner if the divert output line isfull, regardless of the requirement to divert the product. Thus, if thedivert output line is full (YES, step 1512), then the product is passedstraight through the present section and transferred directly into anoutput line, step 1516. Similarly, the product is passed straightthrough and transferred to the output line, when the product is not tobe diverted (NO, step 1510). In this condition, the rollers of thepresent section are not raised, but rather remain in the down or loweredposition.

As with the other sections of the conveying system, the data table 200of the present section is updated to delete the data from the presentsection data table, step 1518 concerning the product being sent onto thenext section of either output line. If the present section is beingcontrolled based on routing information in the data table, then as partof the updating process an informational message is sent by the presentsection controller 10 back to the host computer 8 that the product haspassed through one of the route tags.

Referring next to FIG. 5G, there is shown the section control routinewhen the programmed configuration parameters configure the controller 10so the present section functions as a merge section 114 (YES, step 1036FIG. 5A). For the conveying system of the instant invention, producttraveling along two lines can be merged into one output line using amerge section 114 that applies any of a number or mergingtechniques/criteria. For example, the controller 10 for a merge section114 can be configured the product that first arrives is the firstthrough the merge section 114. Alternatively, the controller could beconfigured so priority is given to one line when product arrives at thesame time in both input lines. For either technique, the merge sectionthereafter alternating receives product from the two input lines. In yetanother technique, a batch of product (e.g., five boxes) is releasedfrom one line and then a batch is released from the other line.

The merge section 114 includes a plurality of rollers that are mountedon a frame so that they can be selectively raised or lowered. Whenraised, the rollers lift the product of the moving belts and act on theproduct on the merge section causing it to change its direction of flowor movement. When the rollers are lowered, the product remains incontact with the moving belts. As such, in one arrangement productpasses through the merge section 114 from one input line directly to theoutput line and in another arrangement, the merge section causes theproduct from the other input line to be re-directed into the outputline.

Preferably, the merge section 114 is preceded by an index section 108 ineach input line as illustrated in FIG. 3. The index sections are used tocontrol the arrival of product from each input line. This keeps productfrom the input lines separate to avoid collisions as well as controllingthe product's time of arrival on the merge section. As such, the mergesection 114 of the instant invention is actuated on the expected arrivaltime of the product from one of input lines on the merge section.Alternatively, the preceding section of each input lines may beconfigured with sensing mechanisms, such as a photoelectric eye as aninput to the present section controller for determining which input lineshould send product and when to actuate the merge section.

In operation, the present section controller 10 (i.e., the mergesection's controller) determines if the stop flag has been set, step1600. If the stop flag is set (YES), then the controller 10 stops theprior sections by sending stop messages to the prior sections, step1602, step 1022 (FIG. 5A). The process then returns to the beginning ofthe control routine for the present section (step 1600).

If the stop flag is not set (NO, step 1600), then the present sectioncontroller performs a status check to see if there is product alreadybeing merged, that is, is there product on the present section, step1606. If there is product on the present section (YES), then the presentsection controller sends a stop message to the controller of the priorsection in each input line, step 1604, step 1022 (FIG. 5A). The productnext to arrive from both input lines is held on the prior sections untilthe present section can accept product for merger and transfer onto thenext section.

If there is no product on the merge section 114 is empty (NO, step1606), then the present section goes through the process of determiningwhich input line to accept product from. The merging process isdependent upon the particular merge criterion/technique to beimplemented by the present section controller. As such, the controllerobtains information from the prior sections of the two input lines andevaluates this against the merge criterion being implemented, step 1608.Preferably, the control routine includes the instructions and criteriafor selectively implementing either of two merge techniques, thepriority merge technique and the batch merge technique.

Using the technique specific instructions and criteria, the presentsection controller controls the merge section, as well as the priorsections of the two input lines, so product is correctly received fromone of the input lines, step 1610. At the same time the present sectioncontroller 10 causes the data table 200 of the present section to beupdated with the information concerning the received product. Inaddition, the controller configures the present section (i.e., rollersraised or kept lowered) at the proper time, so the product beingreceived will be in the proper position for transfer onto the nextsection, step 1612.

After the present section is appropriately configured by the presentsection controller, the product is merged by the present section andtransferred onto the next section in the output line, step 1614. Whenthe product is transferred onto the next section, the present sectiondata table 200 is updated to reflect the departed product (i.e.information deleted), step 1616. Thereafter, the process returns to thebeginning of the control routine for the present section (step 1600).

The following briefly discusses how the forgoing steps are accomplishedwhen using one of the above referenced merge techniques. In the prioritymerge technique, the present section controller 10 determines which ofthe two input lines has priority. If the priority line is, for example,input line #1 then the present section controller determines if there isproduct at the end of the prior section for line #1. This can bedetermined by a signal from a tracking device 122 at the end of theprior section of line #1 or by a signal from the controller of thisprior section indicating that the product is located in the buffer zonefor that section. The present section controller also determines ifthere is product ready to leave input line #2. If there also is productat the end of line #2, then the present section controller sends out aSTOP command message to the controller for the prior section in line #2.

The present section controller then configures the present section toreceive and merge product from line #1 and to transfer it onto the nextsection. For example, if line #1 is in line with the outlet line, thenthe rollers of the present section are left in, or are put in, the downposition. The product passes through the present section on the movingbelts common to the present section, the prior section in line #1 andthe next section.

When the product is transferred to the next section, the present sectiondata table is updated to reflect the departure of the product therefrom.Additionally, if the present section is one of the identified addressesfor a route tag, the present section controller outputs a message to thehost computer 8 as described in the foregoing.

If there is no product ready on line #1, the present section controllerdetermines if there is product at the end of line #2. If yes, then acheck is made to see if product has not just arrived at the end of line#1. If there is product now at the end of line #1, the present sectioncontroller sends a stop message to the controller for the prior sectionof line #1, thereby stopping the product from departing line #1.

The present section controller then configures the present section toreceive and merge product from line #2 and to transfer it onto the nextsection. For example, if line #2 is the angled input line, then therollers of the present section are raised or put in the up position, atthe time the product is expected to arrive on the present section. Therollers are operated to change the direction of the product as it passesthrough the present section. The rollers are then lowered so the productcontacts the moving belts and can move onto the next section. As withthe above described process for line #1, the present section data table200 is updated to reflect the product leaving the present section.

To ensure a space between successively received products, the presentsection controller also does not allow the present section to acceptmore product until after a set time interval has elapsed after theproduct left the present section.

In the batch merge technique, a batch of product is passed through thepresent section from one input line while product is held-up oraccumulated in the second input line. Thereafter, a batch of productfrom the second line then passes through the present section whileproduct is held-up or accumulated in the first line. This processrepeats itself. In all other respects, the process described above forthe priority merge is equally applicable for the batch merge technique.

In the foregoing discussions concerning FIGS. 5B-5E, the respectivecontrol routines being described provided that an elapsed travel timetracking process was initiated by the present section controller 10 aseach box/article entered onto the present section. Referring next toFIG. 5H, there is shown the control routine for the elapsed timetracking process that is used to determine if any box/article wasphysically removed from the present section before reaching thesection's end point. This is done so the tracking of boxes/articles byeach section and the operation of the conveying system is not adverselyaffected by such a removal.

As indicated in the foregoing discussion, as each box/article entersonto a section, a time out clock or clock routine is started 1700. Itshould be recognized that the present section controller 10 may use theclock means of the controller's central processing unit 26, or anotherclock circuit or device, as known to those skilled in the art, todevelop the repetitive signal pulses used to track/determine elapsedtime.

The present section controller 10, using the positional informationdetermined by signals from a tracking device 122, determines if abox/article is located in a buffer zone of the present section, step1702. If the box is in the buffer zone (YES), then the time out clock isstopped for this box, step 1704. While the process describes the clockas being stopped for the box that is exiting the present section, theclock still runs for the boxes remaining on, or added to, the presentsection.

If the box is not in the buffer zone (NO, step 1702), then thecontroller determines if the preset time period for traveling the lengthof the present section should be adjusted, step 1706. As discussedabove, the various sections comprising the conveying system may or maynot be stopped for periods of time (i.e., motion of in-transitboxes/articles stopped). For example, when an accumulation section isthe accumulation mode, the passage of each box through the accumulationsection is delayed. As such, the preset time period is adjusted toaccount for these stoppages or time delays. If the preset period shouldbe adjusted (YES), then the present section controller adjusts thepreset travel time period in accordance with a set procedure, step 1708.

After adjusting the preset travel time period (step 1708) or if noadjustment is required (NO, step 1706), the present section controllerdetermines if the elapsed time for each box exceeds the travel timeperiod for passing through the present section, step 1710. If the presettravel time period is exceeded (YES), then the controller presentsection controller considers the box being tracked to have been removedfrom the present section. Accordingly, the present section controllerupdates the present section data table to delete the informationregarding this box, step 1712 and does not communicate the informationonto the next section. If the conveying system 101 is connected to ahost computer 8, then the present section controller also sends an errormessage to the host computer using the controllers'communicationsnetwork, step 1714 & step 1022 (FIG. 5A).

If the travel time period is not exceeded (NO, step 1710), then theabove process is repeated for the box until the box is determined tohave reached the end of the present section, step 1702 or the presettravel time period has expired, step 1710. As noted above this processis repeated for each box in the present section.

Referring next to FIG. 5I, there is shown the control routine foraccessing the present section controller 10 for the initial programmingor re-programming of the controller's configuration parameters using thebi-directional communications network. Preferably, the host computer 8outputs a message to a controller 10 indicating that it to beprogrammed/re-programmed (YES, step 1004 FIG. 5A).

To program or re-program the configuration parameters, a link isestablished between the host computer 8 and the controller to beprogrammed/re-programmed, step 1800. This typically involves thetransmission of acknowledgement messages between the host computer 8 andthe controller 10 over the communications network 100.

The host computer 8 then transmits the parameters to the present sectioncontroller 10 that are initially being set therein or that are beingupdated or changed, step 1802. For example, when initially configuringthe controller 10 for a straight section 104, the host computer wouldcommunicate information concerning the section type (e.g., 1 for astraight section), the length of the section, the time taken to travelthe length of the section, the next section address, the prior sectionaddress, the size of the buffer zone, and parameters relating to routetagging. Whereas, for example, for updating/re-programming it may changeone of the configuration parameters (e.g., the size of the buffer zone).

The controller 10 takes the transmitted information and stores it in theNVRAM 22, step 1804. The controller 10 and host computer 8 thenundertake a process to verify that the parameters have been properlyupdated/set, step 1806. Thereafter, the present section controllerreturns to monitoring the bi-directional communications network formessages directed to its address, step 1002 (FIG. 5A).

As noted above, each controller also may be initially configured orupdated using the RS232 I/O port 20. In operation, the process forprogramming the controller using the I/O port 20 is similar to thatdescribed above.

While a preferred embodiment of the invention has been described usingspecific terms, such description is for illustrative purposes only, andit is to be understood that changes and variations may be made withoutdeparting from the spirit or scope of the following claims.

What is claimed is:
 1. A conveying system comprising a multiplicity ofconveying sections, each section being provided with a local controllerand wherein the controller for each corresponding conveying section,comprises:at least one bi-directional inflow port; at least onebi-directional outflow port, wherein a communications link isestablished between controllers of respective conveying sections byinterconnecting one bi-directional outflow port of one controller to onebi-directional inflow port of the downstream controller; a processorthat processes information and provides outputs, where at least oneoutput controls the operation of the corresponding conveying section; anapplications program for execution within the processor, wherein theapplications program includes instructions and criteria for processinginformation and providing the processor outputs; and wherein theinstructions and criteria of the applications programincludes:instructions and criteria for communicating information amongand between each controller of the multiplicity of conveying sections,instructions and criteria for processing information received by thecontroller for the corresponding conveying section, instructions andcriteria to control the operation of the corresponding conveyingsection, and instructions and criteria for modifying the operation ofthe corresponding conveying section responsive to informationcommunicated from another controller of another conveying section. 2.The conveying system of claim 1, further comprising a read/write memoryfor storing data and parameters that control the operation of theapplications program and wherein the applications program includesinstructions and criteria for controlling data storage in the read/writememory.
 3. The conveying system of claim 2, wherein the applicationsprogram further includes instructions and criteria for real timetracking of articles on each conveying section.
 4. The conveying systemof claim 2, wherein there are a multiplicity of different section typesfor use in the conveying system; wherein the parameters stored in theread/write memory at least designate the section type of thecorresponding conveying section; and wherein the applications programfurther includes:instructions and criteria to control the operation ofany of the multiplicity of different sections types; and instructionsand criteria for selecting the instructions and criteria that controlthe corresponding conveying section based on the section type parameterstored in the read/write memory.
 5. The conveying system of claim 4wherein one of the multiplicity of different section types is a straightconveying section that transports articles from one end of the sectionto the other end and wherein the applications program further includesinstructions and criteria for operating the corresponding conveyingsection as a straight conveying section.
 6. The conveying system ofclaim 4 wherein one of the multiplicity of section types is anaccumulation section that, under specified operating conditions,accumulates articles on the section and controls their passage onto adownstream conveying section and wherein the applications programfurther includes instructions and criteria for operating thecorresponding conveying section as an accumulation section.
 7. Theconveying system of claim 4 wherein one of the multiplicity of sectiontypes is an indexing section that controls the passage or articlethrough and onto a downstream section and wherein the applicationsprogram further includes instructions and criteria for operating thecorresponding conveying section as an indexing section.
 8. The conveyingsystem of claim 4 wherein one of the multiplicity of section types is aspacing section that controls the release of articles onto a downstreamsection so successively released articles are spaced from each other andwherein the applications program further includes instructions andcriteria for operating the corresponding conveying section as a spacingsection.
 9. The conveying system of claim 4 wherein one of themultiplicity of section types is a merge section that selectively mergesarticles arriving from two input lines of the conveying system into asingle output line and wherein the applications program further includesinstructions and criteria for operating the corresponding conveyingsection as a merge section including receiving data concerning the nextarticle to arrive from the upstream controller in the appropriate inputline.
 10. The conveying system of claim 4, wherein one of themultiplicity of section types is a diverter section that selectivelydistributes articles arriving from one input line into two output linesand wherein the applications program further includes instructions andcriteria for operating the corresponding conveying section as a divertersection including transferring data regarding the article next to bedistributed to a downstream controller in the output line in which thearticle is to be distributed.
 11. The conveying system of claim 4,wherein each controller further comprises at least two bi-directionaloutflow ports and at least two bi-directional inflow ports.
 12. Theconveying system of claim 4, in which the conveying system furtherincludes a multiplicity of tracking devices that sense the presence ofan article, wherein one tracking device is disposed at the beginning ofthe first section and wherein other tracking devices are disposedbetween pairs of conveying sections.
 13. The conveying system of claim2, wherein data relating to the articles on the corresponding conveyingsection is stored in the read/write memory and wherein the controller ofthe corresponding conveying section communicates data relating to anarticle leaving that section to the controller of a downstream conveyingsection that is to receive the departing article.
 14. The conveyingsystem of claim 1, wherein the applications program further includesinstructions and criteria for reprogramming the processor by means ofinstructions and information being communicated to the processor throughone of the at least one bi-directional inflow port.
 15. A method for thelocal control of each device of a plurality of devices comprising thesteps of:providing a local controller for each device to be controlled,each local controller including a processor that processes informationand provides outputs, where at least one output controls the operationof the corresponding device, an applications program for execution withthe processor, and wherein the applications program includesinstructions and criteria for processing information and providing theprocessor outputs; interconnecting the local controllers for each pairof the plurality of devices so as to establish a communications linkbetween the local controllers of said each pair and to establish acommunications network between and among the local controllers of theplurality of devices; controlling the normal operation of the device inaccordance with the instructions and criteria of the applicationsprogram; communicating information between the local controllers of apair of devices relating to at least the operability of at least one ofthe pair of devices; processing the information being received by onecontroller including information regarding the operation of anotherdevice; and modifying the operation of one device responsive toinformation received concerning the operation of said another device.